1. Field of the Invention
The subject invention relates to filtration apparatus, to process filters, and to apparatus and systems for filtering and drying various materials.
2. Disclosure Statement
The following disclosure statement is made pursuant to the duty of disclosure imposed by law and formulated in 37 CFR 1.56(a). No representation is hereby made that information thus disclosed in fact constitutes prior art, inasmuch as 37 CFR 1.56(a) relies on a materiality concept which depends on uncertain and inevitably subjective elements of substantial likelihood and reasonableness and inasmuch as a growing attitude appears to require citation of material which might lead to a discovery of pertinent material though not necessarily being of itself pertinent. Also the following comments contain conclusions and observations which have only been drawn or become apparent after conception of the subject invention or which contrast the subject invention or its merits against the background of developments which may be subsequent in time or priority.
Filtration apparatus or processing filters of the type herein disclosed have been widely used in various industries. For instance, in the chemical industry such processing filters are frequently employed where materials or products are to be separated, filtered, washed, suspended, extracted and/or crystallized, or subjected to a similar operation.
Such processing filters have particular utility in the pharmaceutical industry, where they may, for example, be employed for the preparation of base materials for medicines, pills, powders and the like, as well as for the filtration, washing, crystallization, drying or other processing of various materials and solutions.
Processing filters of this type have an axially symmetrical container which is heatable and is tiltably positioned in a frame. The bottom of such container is provided with a filter permeable to liquids and a powered mixing shaft which is positioned in the longitudinal direction of the container and is adjustable in axial direction by means of a lifting mechanism. The mixing shafts is provided with mixing implements inside the container.
Whereas the filtering and possibly the washing process can be executed in a given container position, the container is typically tilted into a different position for the drying process. Prior-art containers were provided with a support bearing which carried the mixing mechanism, the drive unit and the lifting mechanism for the mixing shaft. However, this arrangement resulted in an excessive total height of the assembly, which was bothersome, particularly during tilting of the container. An additional problem resides in a caking of the processed materials to the mixing mechanism and in particular to the mixing shaft, resulting from the heating effect during the drying process. Caked-on materials had to be removed in a troublesome procedure after the discharge of the product. In addition, this often resulted in a substantial loss of materials.
Furthermore, problems occurred during the tilting process with respect to the arrangement of the numerous requite inlets and outlets of the processing filter, such as the supply and elimination lines for fuel, condensation runoff, filtrate outflow and product supply which all became entangled.
It is already known that placing the stuffing box for the mixing shaft as a rotary structure into an opening into the inside of the container avoids the caking of solid products. Because of this measure the mixing shaft despite rounded container could still be completely inserted into the stuffing box thus avoiding caking. However, since the support bearing was still placed onto the container, the disadvantage of an excessive height of the assembly remained.
For this reason it was already proposed in the German Utility Model No. 78 32 951, German Published patent application No. 28 48 109, and British Published patent application No. 79 26 952, Specification No. 20 34 190, to arrange the support bearing in a container neck within the container itself. According to this proposal, the support bearing is flanged to the lower, plane surface of the neck.
The upper boundary of the bearing slightly extends over the upper container wall. The axial forces are being absorbed by the support bearing at the lower, plane surface of the neck of the container, whereas the seating of the mixing shaft itself takes place between the mixing shaft and the support bearing.
It is disadvantageous, however, that the complete vertical forces which result from the lifting mechanism, the power drive unit and the mixing device itself have to be absorbed by the lower, plane surface of the container neck. An additional disadvantage resides in the fact that the mixing apparatus during operation generates a rotating flexural torque on the lower surface of the neck of the container resulting in substantial stress to the container neck and the container itself. In addition, the accessability to worn parts was poor.
A problem regarding the arrangement of lines existed with respect to requisite tilting of the container. The resulting tangling of lines not only had a negative effect on the performance of the device but it also represented a danger to operating personnel.
For the purpose of tilting the container, an adjustable rack in the apparatus frame meshing with a pinion connected to the shaft of the container was generally provided. Depending on the length of the rack, a certain tilt could thus be achieved. There was, however, a problem with the prior art tilting devices whenever the container was to be fixed in a particular position. In this case the rack would have to bear the total load. The rack generally was moved hydraulically. For this reason, maintaining a tilted position for a longer period of time by means of the hydraulic device alone was not possible since unavoidable leakage losses occurred.
Therefore, a mechanical safety device had to be provided for the more defined positions. It consisted of a bolt inserted into notch-like bores which were arranged accordingly in a part of the container wall and the frame.
This arrangement was disadvantageous, since the container could only be moved in predetermined steps, that is according to the provided bores. The release of the bolt under tension was also problematic.